1. Field of the Invention
This invention relates to a composition of matter and to the process for making such composition which is useful as a low calorie substitute for an edible oil. The low calorie substitute for an edible oil is provided by preparing higher molecular weight polyglycerol polyesters, and alternately, wherein the polyglycerols have been reacted with an epoxide and then esterified.
Presently, one of the most common and difficult problems for people is excessive body weight. This condition is due partly to excessive ingestion of calories and partly to insufficient exercise to expend the calories. The primary source of calories is fat in foods, with each gram of fat supplying about 9 calories. On the whole, fat constitutes about 40% of the total calories in people's diets. Accordingly, in order to reduce the intake of calories, it is necessary that a person reduce one's fat ingestion.
There is certainly adequate motivation for reducing one's calorie intake. Fats have been associated with chronic diseases such as heart disease, cancer and obesity. Therefore, by reducing the intake of fat and the associated calories, many people attempt to also reduce the risk of such afore-mentioned diseases. Besides such physical problems, there are associated psychological problems related to obesity such as poor self-esteem and decreased confidence. Thus, if one's physical appearance is improved, one's mental health is likewise improved. Hence, it would be very beneficial to the general public to replace fatty materials with a food substance having reduced calories.
2. Discussion of Related Art
Recently, a number of fat replacers have been proposed for use in foods. These fat replacers may be divided into two categories, i.e., synthetic fat substitutes and fat mimics. The fat mimetics merely attempt to mimic the mouthfeel of fats. They are carbohydrate and protein based, and as such contain four calories per gram, not the nine calories per gram of fats. They suffer, however, from instabilities to varying degrees and are invariably unstable at frying temperatures. Also, such fat mimetics have not entirely been found acceptable since they do not possess the properties of triglycerides, the main component of natural edible fats and oils. That is, the fat replacer must possess the desirable property of edible fats and oils of being rich in taste and have the textural characteristic associated with a particular food. For example, the rich taste and creamy mouthfeel of ice cream or chocolate is generally attributed to the fat in the food. To have acceptance, a low calorie fat substitute would necessarily have to possess these properties. In addition, such fat substitute should have a color and consistency that is similar to natural edible fats and oils, and if in solid form, should melt smoothly without decomposition to retain the organoleptic properties associated therewith. The organoleptic properties associated with natural edible fats and oils depend upon the fatty acids of the triglycerides. Triglycerides are triesters of glycerine and various fatty acids. The fatty acids may be saturated, unsaturated, cyclic, acylic, oxygenated or non-oxygenated.
In addition, the fat substitute should be oxidatively stable, that is, it should not form color bodies, malodor bodies, nor polymerize any more rapidly than natural fats and oils. Further, the fat substitute should maintain a viscosity close to, and no greater than, that of a natural oil at frying temperatures, for example such as in frying snack foods. The resulting smell, taste and mouthfeel of the fried food must be similar to that of natural edible fats and oils, and not provide a waxy mouthfeel which may be caused by too low or narrow melting point ranges of the fat or oil. These desirable qualities are better attained by the second class of fat replacers, i.e., the fat mimics. These materials try to duplicate the physical characteristics of natural oils.
Another important criteria for a fat substitute is that it not be absorbed by the body when consumed, i.e., it should not be hydrolyzed by pancreatic lipase and thus absorbed through the digestive tract, or if so, only to a minimal extent. In addition, the fat substitute should not cause medical side effects such as diarrhea or anal leakage. Prior art fat substitutes that are not absorbed by the body generally tend to cause diarrhea-like problems when significant amounts thereof are consumed. This problem is said to be overcome by the addition of fats or hardened oils as indicated in U.S. Pat. No. 4,005,195 directed to sucrose polyester fat substitutes, or by providing a more plastic-like oil material as indicated in EP Applications 236,288 and 350,988.
Another type of fat substitute is reported in EP Publication 87 306 468.7 and U.S. Pat. No. 4,861,613 relating to esterified epoxide-extended polyols having the general formula P(OH).sub.a+c (EPO).sub.n (RCOOH).sub.b, wherein P(OH) is a polyol having 1 to 8 primary hydroxyl groups (a), and c is equal to 0 to 8 secondary plus tertiary hydroxyl groups, with a+c being in the range of 3 to 8 hydroxyls; EPO is a C.sub.3 -C.sub.6 epoxide; and RCOOH is a fatty acid acyl moiety in which R is an alkyl chain of at least 7 carbon atoms. The polyols are treated in the presence of a base catalyst with an epoxide to produce epoxide-extended polyols, which is then reacted with a fatty acid to produce the ester thereof. Every hydroxyl group on the polyol is replaced with an ether linkage. Examination of the '613 Patent does not reveal any reference to polyglycols or polyglycerols, only to glycerols.
Polyglycerol esters have been referred to as fat substitutes in the literature. However, these materials are partially esterified polyglycerols that act as emulsifiers and can give some of the mouthfeel of true fats. These materials are only stable at low temperatures. Also, rat feeding studies, described in the literature, have shown that polyglycerol esters, even those termed decaglycerol dodecaoleate, were substantially absorbed, and would therefore also be in humans.
Accordingly, there exists a need for a low calorie fat material that is effective at reducing calorie retention, that does not taste waxy in the mouth, that is stable at elevated temperatures such as during frying of foods, and that does not produce an undesirable laxative side effect.